[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] cdrom disc type - is this patch correct? (unbreaks rec
From: |
Jens Axboe |
Subject: |
Re: [Qemu-devel] cdrom disc type - is this patch correct? (unbreaks recent FreeBSD guest's -cdrom access) |
Date: |
Mon, 19 Nov 2007 10:21:05 +0100 |
On Mon, Nov 19 2007, Juergen Lock wrote:
> Oops, I seem to have missed this post, sorry for not answering earlier...
>
> In article <address@hidden> you write:
> >On Tue, Nov 13 2007, Juergen Lock wrote:
> >> Hi!
> >>
> >> Yesterday I learned that FreeBSD 7.0-BETA2 guests will no longer
> >> read from the emulated cd drive, apparently because of this commit:
> >>
> >http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/ata/atapi-cd.c.diff?r1=1.193;r2=1.193.2.1
> >> The following patch file added to the qemu-devel port fixes the issue
> >> for me, is it also correct? (making the guest see a dvd in the drive
> >> when it is inserted, previously it saw the drive as empty.)
> >>
> >> The second hunk is already in qemu cvs so remove it if you want to
> >> test on that. ISO used for testing:
> >>
> >ftp://ftp.freebsd.org:/pub/FreeBSD/ISO-IMAGES-i386/7.0/7.0-BETA2-i386-disc1.iso
> >> (test by either selecting fixit->cdrom or by trying to install, just
> >> booting it will always work because that goes thru the bios.)
> >>
> >> Index: qemu/hw/ide.c
> >> @@ -1339,6 +1341,8 @@
> >> case 0x2a:
> >> cpu_to_ube16(&buf[0], 28 + 6);
> >> buf[2] = 0x70;
> >> + if (bdrv_is_inserted(s->bs))
> >> + buf[2] = 0x40;
> >
> >medium type code has been obsoleted since at least 1999. Looking back at
> >even older docs, 0x70 is 'door closed, no disc present'. 0x40 is a
> >reserved value though, I would not suggest using that. Given that
> >freebsd breaks, my suggest change would be the below - keep the 0x70 for
> >when no disc is really inserted, but don't set anything if there is.
> >
> >diff --git a/hw/ide.c b/hw/ide.c
> >index 5f76c27..52d4c78 100644
> >--- a/hw/ide.c
> >+++ b/hw/ide.c
> >@@ -1344,7 +1344,10 @@ static void ide_atapi_cmd(IDEState *s)
> > break;
> > case 0x2a:
> > cpu_to_ube16(&buf[0], 28 + 6);
> >- buf[2] = 0x70;
> >+ if (!bdrv_is_inserted(s->bs))
> >+ buf[2] = 0x70;
> >+ else
> >+ buf[2] = 0;
> > buf[3] = 0;
> > buf[4] = 0;
> > buf[5] = 0;
> >
>
> Well that (0) doesn't work. The relevant FreeBSD header,
>
> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/ata/atapi-cd.h?rev=1.46.2.1;content-type=text%2Fx-cvsweb-markup
> , defines the following:
>
> [...]
> /* CDROM Capabilities and Mechanical Status Page */
> struct cappage {
> /* mode page data header */
> u_int16_t data_length;
> u_int8_t medium_type;
> #define MST_TYPE_MASK_LOW 0x0f
> #define MST_FMT_NONE 0x00
> #define MST_DATA_120 0x01
> #define MST_AUDIO_120 0x02
> #define MST_COMB_120 0x03
> #define MST_PHOTO_120 0x04
> #define MST_DATA_80 0x05
> #define MST_AUDIO_80 0x06
> #define MST_COMB_80 0x07
> #define MST_PHOTO_80 0x08
>
> #define MST_TYPE_MASK_HIGH 0x70
> #define MST_CDROM 0x00
> #define MST_CDR 0x10
> #define MST_CDRW 0x20
> #define MST_DVD 0x40
>
> #define MST_NO_DISC 0x70
> #define MST_DOOR_OPEN 0x71
> #define MST_FMT_ERROR 0x72
>
> u_int8_t dev_spec;
> u_int16_t unused;
> u_int16_t blk_desc_len;
>
> /* capabilities page */
> u_int8_t page_code;
> #define ATAPI_CDROM_CAP_PAGE 0x2a
>
> u_int8_t param_len;
>
> u_int16_t media;
> #define MST_READ_CDR 0x0001
> #define MST_READ_CDRW 0x0002
> #define MST_READ_PACKET 0x0004
> #define MST_READ_DVDROM 0x0008
> #define MST_READ_DVDR 0x0010
> #define MST_READ_DVDRAM 0x0020
> #define MST_WRITE_CDR 0x0100
> #define MST_WRITE_CDRW 0x0200
> #define MST_WRITE_TEST 0x0400
> #define MST_WRITE_DVDR 0x1000
> #define MST_WRITE_DVDRAM 0x2000
>
> u_int16_t capabilities;
> #define MST_AUDIO_PLAY 0x0001
> #define MST_COMPOSITE 0x0002
> #define MST_AUDIO_P1 0x0004
> #define MST_AUDIO_P2 0x0008
> #define MST_MODE2_f1 0x0010
> #define MST_MODE2_f2 0x0020
> #define MST_MULTISESSION 0x0040
> #define MST_BURNPROOF 0x0080
> #define MST_READ_CDDA 0x0100
> #define MST_CDDA_STREAM 0x0200
> #define MST_COMBINED_RW 0x0400
> #define MST_CORRECTED_RW 0x0800
> #define MST_SUPPORT_C2 0x1000
> #define MST_ISRC 0x2000
> #define MST_UPC 0x4000
>
> u_int8_t mechanism;
> #define MST_LOCKABLE 0x01
> #define MST_LOCKED 0x02
> #define MST_PREVENT 0x04
> #define MST_EJECT 0x08
> #define MST_MECH_MASK 0xe0
> #define MST_MECH_CADDY 0x00
> #define MST_MECH_TRAY 0x20
> #define MST_MECH_POPUP 0x40
> #define MST_MECH_CHANGER 0x80
> #define MST_MECH_CARTRIDGE 0xa0
>
> uint8_t audio;
> #define MST_SEP_VOL 0x01
> #define MST_SEP_MUTE 0x02
>
> u_int16_t max_read_speed; /* max raw data rate in bytes/1000 */
> u_int16_t max_vol_levels; /* number of discrete volume levels */
> u_int16_t buf_size; /* internal buffer size in bytes/1024
> */
> u_int16_t cur_read_speed; /* current data rate in bytes/1000 */
>
> u_int8_t reserved3;
> u_int8_t misc;
>
> u_int16_t max_write_speed; /* max raw data rate in bytes/1000 */
> u_int16_t cur_write_speed; /* current data rate in bytes/1000 */
> u_int16_t copy_protect_rev;
> u_int16_t reserved4;
> };
>
> [...]
>
> and in
>
> http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/dev/ata/atapi-cd.c?rev=1.193.2.1;content-type=text%2Fx-cvsweb-markup
> a check is done like this:
>
> [...]
> static int
> acd_geom_access(struct g_provider *pp, int dr, int dw, int de)
> {
> device_t dev = pp->geom->softc;
> struct acd_softc *cdp = device_get_ivars(dev);
> int timeout = 60, track;
>
> /* check for media present, waiting for loading medium just in case */
> while (timeout--) {
> if (!acd_mode_sense(dev, ATAPI_CDROM_CAP_PAGE,
> (caddr_t)&cdp->cap, sizeof(cdp->cap)) &&
> cdp->cap.page_code == ATAPI_CDROM_CAP_PAGE) {
> if ((cdp->cap.medium_type == MST_FMT_NONE) ||
> (cdp->cap.medium_type == MST_NO_DISC) ||
> (cdp->cap.medium_type == MST_DOOR_OPEN) ||
> (cdp->cap.medium_type == MST_FMT_ERROR))
> return EIO;
> else
> break;
> }
> pause("acdld", hz / 2);
> }
> [...]
>
> There have been reports of this also being broken on real hw tho,
> like,
> http://lists.freebsd.org/pipermail/freebsd-current/2007-November/079760.html
> so I'm not sure what to make of this...
Well if you ask me (I used to maintain the linux atapi driver), the
freebsd driver suffers from a classic case of 'but the specs says so!'
syndrome. In this case it's even ancient documentation. Drivers should
never try to be 100% spec oriented, they also need a bit of real life
sensibility. The code you quote right above this text is clearly too
anal.
--
Jens Axboe